The death toll from fighting between tribesmen and soldiers in northwest Pakistan has risen to at least 50, the military said.
Major-General Waheed Arshad, the military's spokesman, said that Sunday's fighting occurred in North Waziristan, near the Afghan border.
At least 20 soldiers were also killed in the battle.
Security forces launched an operation in the mountainous area south of the town of Mir Ali after a military convoy was attacked overnight, Arshad said.
Residents said that four civilians had died, including three women.
Pakistan has seen a wave of violence since July, when a peace agreement with tribal leaders broke down in North Waziristan and army commandos stormed the Red Mosque in the capital, Islamabad.
The violence has reinforced opposition among many Pakistanis to the support of the country's president, General Pervez Musharraf, for the so-called US-led "war on terror".
Musharraf has said "terrorism and extremism" are the biggest challenges the country faces and has called for reconciliation among political parties to tackle it.
US officials have warned that al-Qaeda may be regrouping in North Waziristan.